Document Detail

Insulin-stimulated phosphoinositide metabolism in isolated fat cells.
MedLine Citation:
PMID:  2993299     Owner:  NLM     Status:  MEDLINE    
Treatment of isolated fat cells with insulin produced increases of up to 4.8-fold in the incorporation of [3H]inositol into phosphatidylinositol. This effect of insulin was both time- and dose-dependent with half-maximal stimulation at 30 microunits/ml of insulin. Insulin increased the labeling of phosphatidylinositol and phosphatidylinositol 4,5-bisphosphate but not phosphatidylinositol 4-monophosphate in cells which had been preincubated with [3H]inositol for 90 min. Incubation of the cells in a Ca2+-free buffer increased the basal level of phosphatidylinositol labeling and enhanced the effect of insulin. Glucagon and isoprenaline, both of which stimulate lipolysis, had no effect on phosphatidylinositol labeling but did potentiate insulin-stimulated incorporation of [3H]inositol into phosphatidylinositol. Phosphoinositide breakdown was measured by the accumulation of inositol phosphates. Insulin did not increase the level of the inositol phosphates at all concentrations of the hormone tested. By comparison, phenylephrine and vasopressin were able to stimulate phosphoinositide breakdown. Pretreatment of the cells with insulin enhanced the effect of phenylephrine on inositol phosphates' accumulation, suggesting that insulin may potentiate phenylephrine-mediated phosphoinositide turnover. From these data we conclude that insulin stimulates the de novo synthesis of phosphatidylinositol and phosphatidylinositol 4,5-biphosphate, but has no effect on phosphoinositide breakdown.
S R Pennington; B R Martin
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  260     ISSN:  0021-9258     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  1985 Sep 
Date Detail:
Created Date:  1985-10-11     Completed Date:  1985-10-11     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  11039-45     Citation Subset:  IM    
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MeSH Terms
Adipose Tissue / drug effects,  metabolism*
Calcium / pharmacology
Egtazic Acid / pharmacology
Inositol / metabolism
Insulin / pharmacology*
Phosphatidylinositols / metabolism*
Phospholipids / biosynthesis
Rats, Inbred Strains
Reg. No./Substance:
0/Phosphatidylinositols; 0/Phospholipids; 10028-17-8/Tritium; 11061-68-0/Insulin; 67-42-5/Egtazic Acid; 6917-35-7/Inositol; 7440-70-2/Calcium

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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